The last ten years has seen an explosive growth in the development of digital computer systems and technology both in the processing power and of the hardware systems and in the sophistication of the controlling software. Not only has the microprocessor become a ubiquitous incident to almost every laboratory, industrial, and household appliance, but many functions once assigned to combinations of moving parts are almost invariably now preformed by digitally controlled electronics. Systems as diverse as automobile ignition systems and home turntables now share a common electronic heritage. In fact, the performance of many electronic circuits can be equally implemented by hardware or by a digital computer under software control. In many instances the software component of the digital electronics has become enormously complex and correspondingly expensive to develop. Indeed, the cost of the electronic hardware has come down so far that the development time and cost of the software is now the limiting element in the introduction and pricing of many new systems. There has developed, therefore, a great need to reduce the cost and time of software development.
The development over the past three years of what is referred to as "multimedia" computer systems has increased the complexity of the required software as the systems access, simultaneously present, and then replace vast amounts of information. Present systems are directed toward the simultaneous presentation of audio and visual output, but systems are clearly on the horizon which will present coordinated output which can be sensed by all five human senses and create a virtual reality. While present systems access the information for multimedia presentation primarily from local magnetic and optical storage media, it is foreseeable that electronic and optical communication with the world through the coming "information superhighway" will provide a rich source of interactive multimedia
In an attempt to reduce the cost and complexity of developing sophisticated software, attempts have been made over the last few years to modularize software functions with the idea that such modularized software could then be integrated into larger systems to achieve more complex functions. Each piece (object) of modularized software would consist of a set of instructions designed to perform a specific type of task which was frequently required in a more complex program. To use the objects, no knowledge of their internal coding structure would be necessary. All that would be required is to provide the modules with the information (parameters) they required for their use. Thus, applications would be built by selecting appropriate software modules and assembling/ordering/sequencing them to achieve higher order functions. This is the essential goal of "object oriented programming". It quickly became apparent that building with modularized software would not be efficient unless the presentation of the modules themselves conformed to some form of standard; i.e., flat bricks of any material can be stacked, mixed flat and curved bricks, no matter what material they are made of, do not stack well. A second problem facing object oriented programming is that efficiencies of application construction would only be achieved when the assembly of the objects did not require extensive and complex programming itself.
Several attempts have been made, therefore, to develop visually oriented programming systems in which software modules are manipulated as icons which may be arranged/ordered as needed and interconnected with logical operators. Examples of this can be found in the NeXT application development system, in the VIP Macintosh program, and in PowerBuilder, a Microsoft Windows program. Generally, in these types of application development systems, the software modules or objects are presented on a palette from which they are selected and "dragged" into the application under development. Ideally, in these systems, the software instructions needed to integrate the objects into a functioning whole (corresponding to the visual representation or map) are provided by the authoring program system. In reality, most of the prior art systems require the user to write some of the interconnecting software code either in a common higher order language or in a language specialized to that program.
It was hoped that the demand for complex and varied software imposed by multimedia programming requirements could be efficiently addressed by the use of object oriented programming. Until the present invention, these hopes have not been realized. A major problem not solved by the prior art has been the inability to handle in one visual, non-scripted, application development system the diverse requirements of different types of data required by a multimedia program in appropriate visual interfaces.
For instance, during the authoring process a view of the output generated by the application under development is useful when dealing with visual output (images). However, such a view is much less useful for dealing with audio output since, clearly, audio can not be seen. Correspondingly, a time line view in which the elements of the application program are represented by graphs plotting the relative times and sequences of presentation is much more useful for audio. Similarly, a logical map (flowchart paradigm), which visually relates the sequence and logical interconnections of each program element (visual, audio, etc.) is very useful for designing and following the basic structure of the application program. Sometimes, for quickly manipulating or editing particular parts of the developed application code, it is more useful to be able to view the program in a text view and treat the underlying script like a text document. Not only should the application development system provide, at any given moment, a view appropriate to the type of multimedia material being utilized, but such views should be able to be synchronized so that changes made in one view are instantly reflected in all the others. Prior art application development programs do not have the flexibility to present all four views, much less in a synchronized manner. Programs are available which are optimized for output view, map view, timeline view, and script view. Some permit more than one view with some synchronization. However, no prior art program permits access to all four synchronized views. In particular, no prior art program has successfully overcome the difficulty of simultaneously synchronizing the time line view to the other views.
Additionally, in an optimum visual, object oriented, application development program there should be available a wide variety of objects (software modules that would manipulate in different manners multimedia output) with the ability to easily add additional objects, developed by independent programmers, to the development system. Each added object should seemlessly be integrated so that it is available in all four views. Programs of the prior art each have their own object definition standards. That is, for an object to be incorporated into their system, it must meet that program's standards. No prior art program is available which will allow addition of objects not designed to its standard without the necessity of writing additional code to perform the interface to that object. Finally, it should be noted that application development systems necessarily consist of two major parts. The first is the authoring section which provides a customized output (script). The second is a run time system which takes the customized output and executes it. Some prior art run time systems for visually developed applications are notoriously slow in their execution.